Vent structure for electrolytic condensers and the like



y 1941- I J. H. COTTON 2,240,836

'VENT STRUCTURE FOR ELECTROLYTIC CQNDENSERS AND THE LIKE Filed Aug. 18,1938 gu 65% BY 2,,

ATTORNEY.

Patented May 6, 1941 UNETE SAT E i i FFlQE,

VENT STRUCTURE FOR ELECTROLYTIC CONDENSERS AND THE LIKE ApplicationAugust 18, 1938, Serial No. 225,52 l In Great Britain October 30, 1937 7Claims.

The present invention relates to improvements in vent structuresassociated with containers for relieving a container of excess gas orvapors developed therein as a result of temperature changes and othercauses.

More specifically, the invention is concerned with self-closing reliefvents for the containers of electric condensers, in particular, althoughnot necessarily, electrolytic condensers which will normally act to sealthe container but will permit the escape of a gas or vapor when thepressure within the container exceeds a predetermined value.

It has already been proposed in such vent arrangements to close anopening in the condenser container by a diaphragm or membrane of anelastic material such as rubber provided with one or more pin-holepunctures or incisions normally closed by reason of the elasticity ofthe material, the diaphragm being capable of distending when the gasand/ or vapor pressure within the container exceeds a predeterminedvalue so that the puncture or punctures open to permit the gas and/orvapors to escape.

While such vent arrangements normally operate satisfactorily, it isoften found, particularly when they are employed for wet electrolyticcondensers comprising a liquid electrolyte filling the container, thatthe puncture or incision tends to become clogged with electrolyte orother foreign matter so that it no longer acts properly as a valve. Thismay cause in the case for example of an electrolytic condenserundesirable leakage of the electrolyte or liquid constituents thereof,due to the liquid being forced through crevices by the very highpressures which may be set up within the condenser during operation,resulting in a shorter life of the condenser owing to loss orevaporation of electrolyte, the production low resistance paths betweenthe terminals and other defects and drawbacks well understood by thoseskilled in the art.

Accordingly, an object of the invention is to provide an improvedself-closing relief vent of the above general character for electrolyticcondensers or other devices subject to internal excess gas pressure bywhich clogging of the vent opening or puncture by foreign matter and thedefects and drawbacks associated therewith are substantially avoided.

Further objects and aspects of the invention will become more apparentfrom the following detailed description taken with reference to theaccompanying drawing forming part of this specification and wherein,

Figure 1 is a vertical cross sectional View through an electrolyticcondenser of the wet type with the new vent construction according tothe invention embodied therein,

Figure 2 is a partial View of Figure 1 showing a modification thereof,

Figure 3 is a further partial view illustrating a further modificationof the invention.

Similar reference numerals identify similar parts in the several viewsof the drawing.

Referring more particularly to Figure 1, the condenser shown comprises ametallic container I0 of cylindrical or other shape having its upperopen end closed in a liquid tight manner by an outwardly arched cap lloverlying a diaphragm ii of elastic material such as rubber or the likeand secured to the container by spinning or rolling in a known mannerthe edge of the container over the outer rim or flange of the cap H. Inthis manner the outer rim of the diaphragm acts as a gasket to effect aliquid tight seal for the container, while the inner portion serves as avent in the manner described hereafter. tern 13 represents a filmedanode of any desired configuration such as in the form of a pleatedmetal sheet secured to a central supporting rod or riser M, as shown anddescribed in. U. S. patent application 53,567, filed December 7, 1935,in the name of Paul McKnight Deeley. The riser I4 is passed through acentral opening of a resilient plug of rubber or the like forced throughthe outwardly threaded neck [6 of the container with either the plug oropening of the neck or both being of a flaring or conical shape toproduce a liquid tight seal and to hold the anode I3 in a centralposition within the container. The projecting end of the rod Hi servesas a connecting terminal for the anode and for this purpose may beprovided with a connecting lug H or the like in a manner well known.Both the anode l3 and container it may consist of aluminum or any othersuitable metal, at least the anode metal being of the film forming type.Item I8 represents a perforated insulating cylinder or spacer ofCelluloid or other suitable material placed between the anode and innerwall of the container to avoid direct contact between the anode and thecontainer which latter in the example illustrated serves as the cathodeof the condenser in accordance with known practice. The container isfilled with a suitable electrolyte to a sufficient level as indicated atH) and the condenser is preferably mounted in an inverted position suchas shown in the drawing upon a platform or chassis by means of a nut(not shown) engaging the outer threads of the neck IS in a manner wellknown in present day practice.

The inner section of the diaphragm 12 serves as a vent for allowingexcess gas or vapors developed within the condenser to escape to theoutside and for this purpose is provided with one or more punctures orincisions normally closed by reason of the elasticity of the material.If excess gas pressure is developed within the container due to heatgenerated during the operation of the condenser the diaphragm isdistended outwardly toward the cap ll, thereby opening the puncture orincision and allowing the excess gases or vapor to escape to the outsidethrough the escape holes 2| in the cap II.

The diaphragm I2 is preferably provided with an annular collar or spacer23 which may be integral therewith as shown surrounding the puncturedcenter section, whereby with increasing gas pressure at first thediaphragm is distended in its entirety until stopped when the collar 23engages the cap ll, whereupon with further increase of pressure only thecentral punctured section is allowed to distend further and to open thepin-hole or incision and to allow the excess gas to escape therethrough.In order to further improve the operation and to accurately predeterminethe pressure at which the vent opens the central section of thediaphragm is preferably of a lesser thickness than its outer portion asshown in Figure 3. Further details regarding this construction are foundin the above copending application and a further application Serial No.81,252, filed May 22, 1936, by the same applicant.

According to the improvement of the present invention, there is providedat least one sharply pointed or tapered member, referred to as a pin forthe purpose of this specification, being so disposed relatively to thediaphragm that its point penetrates the diaphragm either as thediaphragm distends due to gas pressure within the container or normallyso that it projects through a punctured hole in the diaphragm. Thelatter arrangement is shown in Figure 1 wherein an extension of theriser l4 having a sharply pointed end normally passes through thecentral pin-hole or incision in the diaphragm I2 thereby preventingclogging of the latter by foreign matter and ensuring proper functioningupon the production of excess pressure and distension of the diaphragmas indicated by dotted lines in the drawing.

When the or each pointed member is arranged so as to puncture thediaphragm only when it distends, that is where the point is normally inline with the diaphragm surf-ace, the diaphragm may be initiallyunpunctured so as to seal the container during transport, the diaphragmonly being punctured when it first distends during operation of thecondenser. Alternatively, the diaphragm may be provided with one or morepunctures normally closed by reason of the elasticity of the material,at least one member being in alignment with the puncture so as to passthrough it when the diaphragm distends and thus prevent clogging of thepuncture hole.

An arrangement of the latter type is shown in Figure 2 wherein thepointed member has the form of a rivet 22 secured to the cap II with itspoint normally in line with or just touching the central puncture of thediaphragm I2. Thus, if excess pressure is developed Within thecontainer, the diaphragm will distend as indicated in dotted lines,whereby any foreign matter such as electrolyte, dust particles or thelike which may have entered the puncture hole previously will bedislodged by the pointed member entering the puncture hole therebyensuring ready escape of the excess gas or vapor from the interior ofthe container to the outside.

If desirable, additional means such as a spring may be provided forassisting in returning the diaphragm to its normal position after it hasdistended to permit the escape of gas from within the container, suchmeans preferably being disposed between the diaphragm and the outerapertured cap or cover. An arrangement of this type is shown in Figure 3wherein a coil spring 24 is placed between the central section of thediaphragm I2 and the cap i i. This spring in the embodiment illustratedhas one of its ends formed into a sharp point and bent inwardly andaxially to serve as a pointed member or pin cooperating with thepuncture hole in the manner described. The annular rim or spacer 23 inthis case serves as a positioning means to hold the spring 24 in properposition. Furthermore, in the example illustrated the central section ofthe diaphragm is of lesser thickness than its outer portion for thepurpose described herein above.

The pointed member or pin 22 in Figure 2 may also be formed integralwith the cap H as by extrusion or in any other suitable manner so thatnormally at least one pin is substantially perpendicular to thediaphragm with its point a short distance from the outside surfacethereof and preferably in alignment with the puncture, or normallypassing through the puncture hole in the diaphragm. Thus when, owing toexcess pressure within the container, the diaphragm is distended theaction of the pin will be to dislodge or penetrate through any solidmaterial such as electrolyte, dust particles, etc., which may haveentered into the pin-hole pimcture or incision or may have accumulatedaround the puncture, thereby insuring that there is an adequate openingthrough which the gas can escape. When the gases have escaped thediaphragm returns to its normal position in which it is clear of the endof the pin as in the embodiments according to Figures 2 and 3 orintially penetrates the pin as in the embodiment according to Figure 1.

The diaphragm may be formed and mounted in the container in any desiredmanner, particularly desirable arrangements being those shown anddescribed in greater detail in the above mentioned co-pendingapplications,

The arrangement described and illustrated in application Serial No.81,252, filed May 22, 1936, in which the spacing member in the form of aclosed ring or flange is provided between the diaphragm and an outercap, as shown also in the accompanying drawing (collar 23) and is fixedto or formed integral with either the diaphragm or cap, is particularlysuitable when a spring is provided between the diaphragm and the cap asthis spacing member may serve to position a suitable helical spring andto prevent the latter from being displaced during service as shown anddescribed.

As is understood, the pin may be supported by the anode (Figure 1) orany other part of the condenser or by the cap I I as shown in Figure 2or a special member such as a disc or the like arranged for this purposeunderneath the diaphragm or a coil spring or other additional resilienltspacer provided in the manner and for the purpose described.

While in the constructions according to Fi ures 2 and 3 wherein the pinor pointed member is provided at the outer surface of the diaphragm l2and serves primarily to dislodge foreign matter accumulated within oraround the puncture hole during the dis-tension of the diaphragm, theoperation according to Figure 1 wherein the pin or pointed member isarranged at the inner end of the diaphragm and normally penetrates thepuncture hole therein, the distension of the diaphragm due to gaspressure from within the container not only causes the puncture to openbut also moves the diaphragm outwardly so that a thinner part of thetapered member passes through the diaphragm or [the diaphragm i entirelybeyond the outer end of this member, that is the member is no longer inthe puncture hole. There is thus an ample opening through which the canescape. The container is again sealed when the diaphragm returns to itsnormal po ition. This return may, if desired, be assisted in theconstruction described above by a spring arranged between the diaphragmand the outer cover or cap,

The pin or other pointed tapered member may be of any suitable shape asfor example conical or spade-like, the latter if the diaphragm isprovided with an incision, provided that in the case of a member whichdoes not normally penetrate the diaphragm its end is sufiiciently sharpeither to through a pin-hole puncture or incision or to pierce a freshhole in the diaphragm ma- 1 is member may be of metal or of surfi- Cl-..ly hard insulating material. In the case of electrolytic condensers,a metal member must be of aluminum or other film forming material or ofa metal which does not harmfully react with or otherwise ailect theelectrolyte.

If desired, two or more pins may be so arranged as to penetrate thediaphragm at a corresponding number of points. These pins may all befixed to or formed integral with an outer protective cap or cover or oneor more pins may be attached to or formed integral with a spring orsprings, the remaining pins being carried by the cover in a mannerreadily understood from the above. Alternatively, there may be one ormore tapered members carried by the condenser structure such as theriser or supporting member or the like normally passing through thediaphragm with or without pins attached to or formed integral with theouter cap and/ or springs.

It will be evident from the above that the invention is not limited tothe specific details and at ugements of parts as shown herein forillustration, but that numerous embodiments and modifications of theunderlying inventive idea may be resorted to in accordance with thebroader scope and spirit of the invention as defined by the appendedclaims.

The specification and drawing are accordingly intended to be interpretedin an illustrative rather than a limiting sense.

I claim:

1. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure, comprising a diaphragm ofelastic an arched apertured cap overlying said diaphragm, said diaphragmand cap being secured an opening of said container with the outerportion of said diaphragm forming a sealing gasket between said cap andsaid container, the mid-section of said diaphragm being of lesserthickness than its outer portion and having a puncture hole thereinnormally closed by reason of the elasticity of the material, an annularcollar surrounding said mid-section and projecting towards said cap, acoil spring positioned to have its opposite ends engaging saidmid-section and said cap, respectively, and a pointed member extendinginwardly from said cap through said spring and arranged to engage saidpuncture hole during the distension of said diaphragm.

2. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure, comprising a diaphragm ofelastic material, an arched apertured cap overlying said diaphragm, saiddiaphragm. and cap being secured to an opening of said container withthe outer portion of said diaphragm forming a sealing gasket betweensaid cap and said container, the mid-section of said diaphragm being oflesser thickness than its outer portion and having a puncture thereinnormally closed by reason of the elasticity of the material, an annularcollar surrounding said mid-section and projecting towards said cap, acoil spring positioned to have its opposite ends engaging saidmid-section and said cap, respectively, and a pointed member extendinginwardly from said cap substantially at right angle to said mid-sectionand having its point in line with and normally engaging the outer end ofsaid puncture.

3. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure, comprising a diaphragm ofelastic material, an arched apertured cap overlying said diaphragm, saiddiaphragm and cap being secured to an opening of said container with theouter portion of said diaphragm forming a sealing gasket between saidcap and said container, the mid-section of said diaphragm being oflesser thickness than its outer portion and having a puncture holetherein normally closed by reason of the elasticity of the material, anannular collar surrounding said mid-section and projecting towards saidcap, a coil spring positioned to have its opposite ends engaging saidmid-section and said cap, respectively, and an extension of said coilspring bent radially and axially to provide a pointed member in linewith and arranged to engage said puncture hole during the distension ofsaid diaphragm.

4. A vent for an electrolytic condenser and the like having a containersubject to internal excess gas pressure comprising a diaphragm ofelastic material, a cap overlying said diaphragm, said diaphragm and capbeing secured to an opening of the container, said diaphragm having apuncture normally closed by reason of the elasticity of the material andadapted to be opened by outward distension of the diaphragm under theaction of a predetermined gas pressure developed within the container,and a coil spring arranged with its opposite ends engaging saiddiaphragm and cap, respectively, and having a pointed extension arrangedaxially thereof and in line with said puncture.

5. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure, comprising a diaphragm. ofelastic material, a cap overlying said diaphragm, said diaphragm and capbeing secured to an opening of said container, said diaphragm having a,puncture normally closed by reason of the elasticity of the material andadapted to become opened by outward distension of the diaphragm underaction of a predetermined excess gas pressure developed within saidcontainer, a resilient spacing member intervening between the distendingportion of said diaphragm and said cap, said member consisting of amaterial having a more permanently maintained elasticity than saiddiaphragm and being provided with a pointed projection arranged toengage said puncture.

6. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure comprising a diaphragm ofelastic material, a cap overlying said diaphragm, said diaphragm havinga puncture normally closed by reason of the elasticity of the materialand adapted to become opened by outward distension under the action of apredetermined excess gas pressure developed Within the container, and aresilient spacing member intervening between the distending portion ofsaid diaphragm and said cap and having a more permanently maintainedelasticity than said diaphragm, said resilient member having a pointedprojection arranged to engage said puncture.

7. A vent for an electrolytic condenser or the like having a containersubject to internal excess gas pressure comprising a diaphragm ofelastic material, a cap overlying said diaphragm, said diaphragm having.a puncture normally closed by reason of the elasticity of the materialand adapted to become opened by outward distension under the action of apredetermined excess gas pressure developed within the container, and acoil spring having a more permanently maintained elasticity than saiddiaphragm and arranged with its opposite ends engaging the distendingportion of said diaphragm and said cap, respectively.

JAMES HENRY COTTON.

